- Solar is the cheapest power to the grid
- The EROEI (or energy profit) of Solar is fine – first it’s easier to calculate than thermal systems
- Cleantechnica February 2018 says:
- One of the founders of the EROEI concept says solar EROEI is fine!
- Solar growth has been spectacular – but more is required!
- But it will use too much land?
- Utility solar costs half rooftop solar!
- Can we recycle solar panels yet?
Solar is the cheapest power to the grid
As IRENA says:
The cost of manufacturing solar panels has plummeted dramatically in the past decade, making them not only affordable, but also often the cheapest form of electricity. Solar module prices fell by up to 93% between 2010 and 2020. During the same period, the global weighted-average levelised cost of electricity (LCOE) for utility-scale solar PV projects fell by 85%.
The EROEI (or energy profit) of Solar is fine – first it’s easier to calculate than thermal systems
Is calculating EROEI of solar harder than for fossil fuels or nuclear?
As stated at the beginning of the previous paragraph, the calculation of energy costs for photovoltaic solar energy is much simpler and more accurate than for energy feedstocks (and for the corresponding sectors of the electricity industry based on burning hydrocarbons), as well as nuclear energy. The reason for this is simple: the bulk of the energy costs associated with the life cycle of a solar power plant falls on the stage of standardized, high-tech industrial production. Roughly speaking, the main energy costs are made at the plant. The plant is connected to the relevant energy supply systems with the appropriate energy accounting systems.
To the question of EROI (EROEI) of solar energy at Medium – Nov 2022
That is, once you count the mining and energy used in the factory production system, you don’t have to also account for ongoing mining and refining of the various fuels going into the mining and refining and transport of fossil fuels.
Cleantechnica February 2018 says:
SHORT ANSWER
Myth: solar energy has low, even counterproductive, energy return on energy investment (ERoEI)
Short answer: Actually, solar energy has superb energy return on energy investment (ERoEI) — 1 to 4 years, according to the US National Renewable Energy Lab, or 1 to 2.5 years in Europe, according to the Fraunhofer Institute in Germany.
LONG ANSWER
This criticism has been proven to be false, and may be nothing more than a deliberate form of misinformation intended to persuade people who are interested in solar power to lose that interest. Too often, the critics turn out to be people who are directly or indirectly connected to fossil fuel industries like oil and gas, nuclear, or coal. They also may be politically conservative — certain highly politicized members of that group have historically opposed renewable energy to some degree.
Let’s look at what a neutral scientifically focused source, the US National Renewable Energy Lab, says about solar power and the energy payback situation: “Energy payback estimates for rooftop PV systems are 4, 3, 2, and 1 years: 4 years for systems using current multicrystalline-silicon PV modules, 3 years for current thin-film modules, 2 years for anticipated multicrystalline modules, and 1 year for anticipated thin-film modules (see Figure 1). With energy paybacks of 1 to 4 years and assumed life expectancies of 30 years, 87% to 97% of the energy that PV systems generate won’t be plagued by pollution, greenhouse gases, and depletion of resources.”
The Fraunhofer Institute in Germany published a document containing similar figures: “The Energy Payback Time of PV systems is dependent on the geographical location: PV systems in Northern Europe need around 2.5 years to balance the input energy, while PV systems in the South equal their energy input after 1.5 years and less, depending on the technology installed.” Its report also noted there was a PV system in Sicily with a payback time of about one year.
In other words, PV solar systems today easily generate enough electricity to equal the amount of energy consumed to produce them. They then go on for many years to produce clean electricity.
The Fraunhofer Institute has a 2023 Report (PDF) with this fantastic graph of micro-grams of silicon used in cells each year declining over time. Less silicon means more efficient panels, easier to make – and yet the technology keeps increasing solar output over time!
Eclipse Comment: What about areas of cheap real estate like farms or factory rooftops?
Maybe after their lifetime of 30 years domestic users would want to replace them – but what about utilities out in areas with really cheap real estate? Would they care if the panels were much less efficient – as long as they still had some output? It depends how abundant the land area is for it, but I can imagine panels being left out 40 years or so – radically increasing their total lifetime energy payback.
One of the founders of the EROEI concept says solar EROEI is fine!
The founders of the EROEI concept were Professor Charles Hall and David Murphy. They originally concluded that the Energy Return on Energy Invested of renewables was not high enough to run the modern world. But studies into this have a huge range.
“Studies have given figures for the EROI of solar energy as low as 3.9 and as high as 45.45. The lowest estimate, produced by Weissbach et al, was thoroughly discredited by technology entrepreneur Ramez Naam as glaringly low, and he estimates the EROI of solar PV at “above 10, and probably above 15…And rising.” In the most thorough meta-study of the EROI of solar PV, conducted by Bhandari et al, 232 papers estimating solar’s EROI were analysed and the mean estimate was 11.6. Mean EROI varied greatly between types of solar PV, with cadmium telluride coming in at an astounding 34.2. It is also important to note that many of these studies focussed on older installations, which lowered the average. Most modern studies find an EROI for polysilicon solar PV of about 16 and future systems will continue to rise.
In a similar meta-study, systems ecologist Charles A.S. Hall as well as researchers Jessica Lambert and Stephen Balogh looked at the data in studies of other energy sources. Their results are shown in the following table (except for solar – due to their results underestimating its EROI by including decades old studies, Ramez Naam’s estimate of 15 is used).“ https://www.vikramsolar.com/eroi-of-solar-energy/
David Murphy critiqued some of his earlier work with Charles Hall, and said certain EROEI system boundaries needed streamlining. So he did a meta analysis of the literature and clarified those. With efficiency gains more solar panels are made from less materials, Dr David Murphy now categorically puts solar at 10 and oil down at 4.6! That’s one of the FOUNDERS of the very concept of EROEI saying solar is now higher than oil. https://www.sciencedirect.com/science/article/pii/S0301421513003856
Solar growth has been spectacular – but more is required!
As the IEA says (September 2022)
Solar PV generation increased by a record 179 TWh (up 22%) in 2021 to exceed 1 000 TWh. It demonstrated the second largest absolute generation growth of all renewable technologies in 2021, after wind. Solar PV is becoming the lowest-cost option for new electricity generation in most of the world, which is expected to propel investment in the coming years. However, average annual generation growth of 25% in the period 2022-2030 is needed to follow the Net Zero Emissions by 2050 Scenario. This corresponds to a more than threefold increase in annual capacity deployment until 2030, requiring much greater policy ambition and more effort from both public and private stakeholders, especially in the areas of grid integration and the mitigation of policy, regulation and financing challenges. This is particularly the case in emerging and developing countries.
But it will use too much land?
As the Blakers team say:
To eliminate all fossil fuel use, Australia would need about 60 square metres of solar panel per person, and one wind turbine per 2,000 people. Panels on rooftops take up no land, and wind turbines use very little. If global energy consumption per person increased drastically to reach Australian levels, solar farms on just 0.1% of Earth’s surface could meet this demand.
Don’t let anyone tell you you there isn’t enough LAND for solar. If we cover half the world’s rooftops with solar, it would provide all today’s electricity needs. Cover all the world’s rooftops and we are on the way to electrify transport.
Also – why not float the solar on water? It reduces evaporation of precious fresh water from our reserves and keeps the solar panels cool to stay efficient.
As Dr. Thomas Reindl of the Solar Energy Research Institute of Singapore said in the video above – just 10% of the world’s water reservoirs would give us all the electricity we need to decarbonise the electricity sector. But to also replace transport oil and industrial heating – we’ll have to double it. So to illustrate the scale – just 20% of our water reservoirs and we’re done.
It gets better. For an extra bonus – America’s NREL concluded that 7.6 terrawatts of potential power per year would be from floating solar on existing hydropower dams. In other words – they’re already wired into the grid!
Now, what about floating on calm seas out between the islands of Indonesia and other calmer waters? The potential here is vast:
…up to one million TWh per year. That’s about five times more annual energy than is needed for a fully decarbonised global economy supporting 10 billion affluent people.
Professor Andrew Blakers – August 2023
If you didn’t catch it – that’s enough power to give 50 billion people modern lifestyles. But if you’re sceptical about floating solar and all that (I’m not! It’s just happening!) – the Land art generator shows there’s nothing to worry about.
Utility solar costs half rooftop solar!
Titled Comparative Generation Costs of Utility-Scale and Residential-Scale PV in Xcel Energy Colorado’s Service Area, this study is the first to focus on a “solar to solar comparison of equal amounts of residential-scale and utility-scale PV solar deployed on an operating utility system.”
The study found that the cost of generating energy from 300 MW of utility-scale PV solar is roughly one-half the cost per kWh of electricity produced from an equivalent 300 MW of 5kW residential-scale systems when deployed on the Xcel Energy XEL +0% Colorado grid. Utility-scale solar remained more cost effective in all scenarios considered in the study, scenarios having different tax credits, monetizations, and inflation rates.
James Conca in Forbes, July 2015
But it’s still worth having your own rooftop solar – specially given the crazy power prices of the last few years!
Can we recycle solar panels yet?
It certainly seems so – check the Recycling Renewables page.
Eclipse Now 
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