Renewable energy systems – Practical aspects
Updated: Apr 11, 2021
In our previous article we commented on opportunities and challenges in electrification. This article is the last of four, elaborating on practical aspects around installing and managing renewable energy systems, in particular solar-based systems – and having worked with planning, implementation and operation of telecom networks for many years, this is of a quite similar nature.
The joint goal of the four articles is to enhance the awareness of the energy situation today, how energy may influence emissions and improve daily lives and business, looking into some of the related challenges and solutions - and the fact that we all have a role to play in order to take responsibility for speeding up the required energy transition in the world. The first and second articles were more specifically on energy and the climate and on solar energy and applications.
Operation & Maintenance
As global markets develop both in the developed and developing parts of the world, the long-term reliability and performance of solar PV-systems should gain increasing attention, as these strongly affect a project’s bankability and presumed ROI. Depending on the actual global market, solar panels face various physical challenges of dust, wind, snow and damage by humans or animals. In markets where power plants have already aged, the industry has realized that proper “health care” is indispensable for power plants to meet performance expectations. Developments in IoT sensors, machine learning and edge computing will help to enhance the features and capabilities of current models, so that predictive maintenance becomes a ubiquitous tool across the industry.
To obtain maximum performance for solar-panels, inverters and batteries, qualified and certified personnel and toolkits should be used during installation and operation, and regular O&M best practice guidance in the industry and region should be followed - not to forget requirements for environmental and social responsibilities. Commercially available predictive maintenance systems are now increasingly being developed by manufacturers, available for utility companies, operators of large-scale solar-parks and APV farms. Optimum-sized home-PV systems normally don’t need other maintenance than panels surface cleaning, if at all needed, and regular observation of performance data to find any abnormalities.
Among the three typical maintenance philosophies, Preventive (at regular intervals), Corrective (if something breaks) and Predictive (before faults occur), the latter has shown substantial results in companies having implemented this model: Cost reduction 12%, Uptime improvement 9%, HSSE improvement 14% and Extension of Life 20%. Hence, improved results and prolonged time until End of Life can be achieved.
Reliance on a central utility producing and transmitting electricity is fading, and utility companies will need to shift their business models. Soon, they will no longer be the sole source of energy, but will be needed to maintain a balanced grid, shifting electrons from disparate sources and storage systems to seamlessly deliver energy where it is needed second-by-second. Consider the Distributed Energy Resources (DERs) as individual musicians, a utility company is a conductor keeping the orchestra in sync as AI composes the symphony in real-time.
Under a new regime of bidirectional load on the utility grid, also the grid should be operated under optimum conditions to always obtain maximum performance. Use of sensors on the power lines may pick up variations in temperatures in the cable itself and its environment. This will enable detection of wire temperatures reaching levels up to 30-40 degrees which may reduce the transmission efficiency as well as detect upcoming icing problems on the wires during winter season. Information on the conditions at the physical structure of the grid may offer the utility companies the ability to actively utilize alternative resources to bring down temperatures or being proactive to prevent icing.
End of Life
It is sad to recognize that large volumes of solar panels are still produced by fossil energy e.g. from coal plants - especially in Asia. Today, 70% of all solar panels are produced by Chinese manufacturers using the energy-intensive “Siemens process” and a Chinese energy mix
with a large share of coal power. In Norway we are proud to acknowledge the company REC Solar that over 30 years has been working to develop the most environmentally friendly process possible for production of solar cell silicon. This is the raw material for 95% of the solar cells produced today, and normally accounts for almost half of the climate footprint of a standard solar panel.
Since 2009, REC Solar in the city of Kristiansand has supplied solar cell silicon that has been produced with a metallurgical cleaning method in three steps, instead of going via the gas phase. The result is a significant cut in energy consumption and thus CO2 footprint. Yet another and improved process is based on the established metallurgical process but using the waste from the process where the silicon blocks are sawn into 0.2mm wafers, and then using this saw dust, cleaning it back to solar cell quality. The climate footprint of electricity produced from a solar panel will vary with both the production method and where they are installed. Electricity from coal power will in any case have a footprint that is well over 10 times as large as the Siemens process with Chinese energy mix.
Even though solar energy is emission-free and entails little intrusion on the nature, the solar panels in projects we are building today will turn into a large waste stream in a few decades. In some markets this process has already started. A solar plant may be operational for 20-40 years, and even then, there may be room for a second-hand market. Most players in the industry will even exist shorter than the lifetime of the products they supplied.
As PV-systems reach their EoL milestone at residential or industrial plants, decisions must be taken whether the assets may be candidates for resale and reuse, given a new life in secondary markets, or if they should be recycled to get the maximum out of its original raw materials. Anyway, a proper dismantling and decommissioning process must be followed, either for replacement with the latest technology in a new PV-system or for termination of service and complete removal only. To meet sustainability goals, this process should be given proper attention to mind the importance of a circular economy and renewable resources. Mind also that processes must be in place to inform the interconnected utility companies if production capacity is halted and/or permanently displaced.
Provision of electricity for heating/cooling has since the beginning given advantages for humans, but with various impacts on the environment and the nature. Hydro-energy based on water-dams, coal-based energy from mines and huge polluting powerplants for nuclear energy all have strong impacts. Renewable energy requires wind turbines mounted on land or off-shore, and in a similar way for Solar-plants on fjords, waters or on land. Our societies cannot do without energy, and now as renewables are being deployed in large volumes, this may change fjords, coastlines, the landscape and surrounding nature for decades to come.
As development of offshore wind projects occur, area conflicts with marine ecosystems, fisheries and other interests emerge. In the ocean, there are rich and vulnerable marine ecosystems with birds, fish, marine mammals, benthic animals and corals. One of the major problems in the development of wind power on land has been very inadequate surveys of species, habitats and natural carbon storage. The knowledge base has been too poor, but as we have little knowledge about nature on land, we have even less knowledge about nature in the sea.
Far out at sea, there are hardly any hobby botanists who register species in their spare time, as they do on land, which has led to hard resistance in the public opinion about onshore wind power. Hence, at sea the responsibility for authorities becomes all the greater, to get an overview of the animals' migration routes, spawning areas and important natural values, and to ensure that offshore wind development is not allowed in areas that are important for birds, fish and other marine life.
Some of the best weapons in the fight against climate change are preservation of forests and intelligent deployment of on-/offshore renewable energy, and both need to succeed. Deployment of utility-scale renewable energy projects like ground-mounted solar arrays should be erected in already-developed areas, not focusing on less-expensive rural open spaces, natural beauty of valleys and lakes in mountainous areas. Neither wind-turbines nor racks of solar panels in dedicated parks will enrich any parts of our natural landscape and environment, and long-term decommission agreements should be in place to ensure proper clean-up and restoration, upon the said gear’s potential End of Life.
A crucial goal should be to reform renewable-energy programs to provide incentives to accelerate solar in already developed and disturbed locations, such as rooftops, facades, landfills, brownfields, and parking lots - and to stop any incentives that are encouraging the clearing of forests and natural areas to make way for solar development. The same goes for wind-energy projects, as in this case even the visual and audible effects of turbine-towers should be carefully considered, to avoid conflicts with people, animals and agriculture.
Investors know that if a roof leaks, it most likely poses a serious problem. Roofs must be repaired or replaced, but for ground based solar this problem does not apply. It may also be hard to coordinate Building Integrated Photo Voltaics (BIPV) projects with authorities in urban areas. So, everyone – utilities, owners and investors for large-scale solar solutions, may prefer to go to the ground. Clear community policies and frameworks are needed to avoid undesired long-term effects and results.
The fight against the changing climate is like a three-legged stool, where all the legs are needed: 1) cut greenhouse-gas emissions as quickly as possible; 2) conserve energy and use it efficiently to reduce demand; and 3) conserve forests to absorb and store carbon.
Environmental effects in production & operation
Finally, or maybe primarily for the next generations, the environmental effects and desire to contribute to a carbon neutral world should hopefully engage and motivate for investment and deployment of PV-based energy systems, privately and in businesses. The solar cells (and batteries) should though preferably having been produced as per EPD «Environmental Product Declaration», certifying low CO2 footprints, and mining of raw materials performed with care for HSSE and without the use of child labor. The visibility of solar panels on private homes or real-estate of business and public buildings will send a signal to the communities that environmental responsibility has been taken.
It should be noted that for a PV-systems at a single-family home a reduction of electricity-related CO2 emissions of the households could be reduced by some 45%, according to EUPD Research. If a battery is included, then the CO2 emissions can be reduced further up to 85%. Houseowners of any size may control and reduce their energy consumption by introduction of an Energy Management System that runs the IEEE 2030.5 protocol which is an open international protocol for Smart Energy communications designed for consumer and residential devices. The EMS will manage Utility supply and equipment such as inverters for Solar Panels, Heat Pumps, Electric Vehicles, Stationary Batteries and large electricity consumers within the building. Consumer energy optimization will ease the load on the grid too.
Given that we potentially may electrify everything going forward, electrical energy can be used to perform most of the operations required to make our technology-based societies function. Electricity can be produced using wind turbines, solar panels, hydroelectric plants and other renewable forms of energy, making a difference in the emitting of carbon pollution from “green” energy to on average less than 30 gCO2/kWh compared the contribution from methane’s 400 gCO2/kWh and coal’s 1,000 gCO2/kWh. In fact, procurement of PV and batteries should not only be price/quality based, but also considering carbon footprint of production, as we globally approach 4,000 billion excess tons of CO2 in the atmosphere, and annually adding 230 mill tons/year.
Can Solar energy produce higher efficiency with new technology, techniques, materials and/or construction, reducing the footprint of ground-based PV-panels both on land and water? For example, Concentrated Solar Power (CSP) plants use mirrors to concentrate sunlight onto a receiver, which collects and transfers solar energy to a heat-transfer fluid. This can be used to supply heat for end-use applications or to generate electricity through conventional steam turbines, and large CSP plants can be equipped with a heat-storage system, for night and cloudy periods. CSP efficiency is system dependent from 15-30%, whilst expectations go even beyond.
Solar water desalination and irrigation system replacement
The agricultural sector holds a high demand for fresh water, which will be boosting the global solar based water desalination market. The desalination systems running on solar power are considered to be cost efficient, and can be applied for all commercial, industrial and residential sectors. Other factors aiding in expansion of the global solar based water desalination include easy operation, low maintenance, easy installation for onshore and offshore activities, and climate control.
Population growth, especially in developing nations, coupled with the increasing urbanization worldwide, is likely to impose expansion of solar based water desalination. Additionally, the rise in operating costs of desalination plants is less than other water preservation techniques, consequently increasing its preference, especially in rural areas of emerging markets – e.g. integrated as part of mini-/micro-grids, functioning as an enabler of agriculture in former wasteland areas.
Solar panels on water, lakes and canals, may increase electricity production due to the cooling effect, and may serve as replacement for irrigation systems in agriculture. Covering California's canals in solar panels could save 63 billion gallons of water annually, which is comparable to the amount needed to irrigate 50,000 acres of farmland. Researchers tested the thesis that by erecting a modular system of solar shading panels over California’s exposed aqueducts, the state can reduce evaporative water loss and provide a variety of benefits when compared to conventional ground-mounted solar systems. The 13 GWs of solar power the solar panels would generate each year would equal roughly half the projected new capacity needed by 2030 to meet the state’s decarbonization goals. Nothing is said, however, whether adjacent societies, industry and utility infrastructure would be able to consume produced volumes.
Security and availability aspects
On our way towards a distributed, decentralized and software-optimized energy pro-sumption infrastructure, it is unavoidable that both end-users (private/commercial) and utility companies will open potential opportunities for hackers through sophisticated computer attacks as recently experienced in the case of the recent Solarwinds attack (refer also one of our earlier articles). This may open for severe incidents which our societies and private homes have never before experienced. Transactions for exchange of energy between utilities and prosumers in smart energy networks, even directly between consumers themselves, could result in economic consequences as well as operational stability issues.
In order to save energy, household systems will in the future become increasingly connected and start communicating to each other so that e.g. not everyone's elements are on maximum at the same time. With more available data, however, the risk of security and privacy breaches increases, something that could, as an example, lead to burglary after a hacked measurement of a villa's reduced energy use during holidays. A new EU project will reduce the risk of such incidents with the help of AI-based collective intelligence.
The risk of security and information breaches caused by hackers and its consequences may be even more severe for utility companies, solar/wind-park operators, community networks and micro-grids, utility-scale solar plants, etc. Internet-enabled smart inverters are especially at risk because they communicate with the grid to perform management functions. There are potentials for hackers to tap into these inverter communications, throwing the grid voltage out of control, which could lead to brownouts or blackouts. The damage potential is especially alarming when compounded with the increasing frequency of natural disasters.
Research labs and inverter manufacturers are taking steps to ramp up cybersecurity within the inverter itself. However, the flow of information on the grid is really complex. There are market and load management systems that communicate with balancing authorities connected to utility companies. These systems tap into project supervisory control and data acquisition systems and, finally, the power plant controller. This leaves a lot of links within the chain vulnerable to cybersecurity risk.
Surveillance, control, optimization and load prediction, hence infrastructure utilization, will require sophisticated systems that hold real-time interaction with numerous network nodes and microgrids, power generators and batteries for supply and electricity storage, and a mix of private and commercial consumers. Even data from weather forecast of wind, solar, temperature and the stock market of power supply and pricing will need to be included in order to keep and maintain service levels on daily, short term basis and as reference for future planning and deployment.
There is a need for technology development in solar energy in order to provide solar panels/devices that obtain more energy and occupy less space - and wind-turbines with higher efficiency using less voluminous tower-turbines. Technologies for energy storage will be the essential element to support renewables in the ongoing transition and build-up of infrastructure for the grid, both smaller micro-grids as well as battery parks for high volume energy storage. It is expected that we may be witnessing similar development for this technology as observed last decades for solar energy in particular.
Having seen great progress in terms of increased efficiency and decreased prices for renewables in only the last couple of decades, there should be hope that this development may continue for the coming years, enabling the demand for energy globally to be met with minimal effects on nature and our environment.
However, a strong reduction of CO2 emissions and carbon capture is required, and the energy transition from fossil to renewable energy must speed up significantly to reach our goals of a sustainable future. Here the energy transition of the electrified grid is essential, with the revolution by introducing decentralized, distributed energy resources. So far, we have only witnessed the beginning.