Renewable Energy
The sun sends no bill. The fight is over who controls the wires, storage and profits in between.
Renewable energies are sources that renew themselves as long as the sun shines and the Earth turns. Unlike coal, oil or uranium, they do not run out: the wind will blow again tomorrow, the river keeps flowing, the sun comes back every day. That is exactly what makes them so interesting, and at the same time so inconvenient for everyone whose business rests on scarce, sellable fuels.
What counts as renewable?
The renewable energies include the sun (as solar electricity and as heat), the wind on land and at sea, hydropower from flowing and dammed waters, biomass (wood, plant residues, biogas) and geothermal heat from the hot interior of the Earth. Almost all of them are, as shown in the previous chapter, ultimately converted solar energy. The hallmark is always the same: we tap into an ongoing flow instead of plundering a finite store.
The trick with the percentages
When the news says renewables cover "more than half," a critical follow-up question is worth asking: half of what? Almost always what is meant is electricity. But electricity is only one part of our hunger for energy. On top of it come heat (heating, hot water, industry) and transport, and there the renewable shares are to this day considerably smaller.1 Whoever confuses electricity with total energy either takes us to be further along than we are, or talks down the progress. On close inspection, advertising and reality part ways.
Where do we stand?
Germany now covers more than half of its electricity from renewable sources, above all from wind and sun.1 Count in heat and transport and the share of total energy consumption drops to roughly a fifth. France traditionally relies heavily on nuclear power and therefore has low CO₂ emissions in its electricity, but a comparatively smaller build-out of wind and solar. In the European Union, just under a quarter of total final energy comes from renewables, with large differences between countries. The United Kingdom has above all strongly expanded offshore wind power in the North Sea, while the United States, despite enormous additions of solar and wind, lags behind proportionally because of its high total consumption.2 In short: movement everywhere, but no country has reached the goal.
What is most promising?
The most honest answer is given by the price. Solar (photovoltaics) and wind have become so cheap over the last fifteen years that today they are usually the cheapest way to generate new electricity, cheaper than new coal or nuclear plants.2 Both can be set up quickly and scaled at will, from the small house roof to the huge wind farm. Hydropower is strong but largely built out; biomass and geothermal play more of a supplementary role.
The real challenge is not generation but rhythm: sun and wind do not deliver on demand. The future will therefore be decided by storage (batteries, hydrogen, pumped storage), by smart electricity grids and by matching consumption and generation better to one another. Whoever solves this wins, and this is where new dependencies and questions of power are arising: who owns the grids, the storage, the roofs?
Is that enough without saving?
This brings us to the most uncomfortable question: can we cover our present energy needs in Europe entirely from renewables in the foreseeable future, without saving? Technically a transformation is possible, but the higher consumption stays, the more land, raw materials, storage and lines it requires, and the more expensive and slower the transition becomes. That is why efficiency (the same with less energy) and sufficiency (some things simply more consciously and less) are not spoilsports but the strongest allies of renewables. As shown in the previous chapter: more quality of life is entirely compatible with less energy consumption. Every kilowatt-hour saved need not be generated in the first place.
The narrative that we could simply consume ever more and solve everything with new technology is convenient, but it shifts the responsibility. The emancipatory view is the opposite: we ourselves shape how much we need and for what. The sun sends no bill, but whether its energy benefits everyone or a few is not a physical question but a political one.
What does the kilowatt-hour cost?
Numbers say more than opinions. The following table shows rough levelized costs for new installations, that is, what a generated kilowatt-hour (kWh) roughly costs when construction, operation and financing are spread over the lifetime (here simplified to about 20 years). The values are rules of thumb in cents per kWh and vary greatly depending on location, size, interest rates and weather.3
| Energy form | Electricity or heat | ≈ Cost (ct/kWh) | Note |
|---|---|---|---|
| Solar electricity, open field | Electricity | 4–7 | currently often the cheapest source of power |
| Solar electricity, house roof | Electricity | 7–12 | smaller, but power right where it is used |
| Solar heat (solar thermal) | Heat | 6–12 | for hot water and heating support |
| Wind power on land (onshore) | Electricity | 4–9 | strongly dependent on location |
| Wind power at sea (offshore) | Electricity | 7–12 | high yield, but costly to build |
| Hydropower | Electricity | 5–15 | existing plants very cheap, new build costly |
| Biomass / biogas | Electricity | 10–20 | controllable on demand, but costly and limited |
| Geothermal, near-surface (heat pump) | Heat | 8–15 | depends on the pump's electricity price |
| Geothermal, deep (deep geothermal) | Heat | 4–10 | high upfront costs, drilling risk |
| Geothermal, deep (electricity generation) | Electricity | 15–30 | economical only at favourable sites |
Three things should be kept in mind while reading. First: electricity and heat cannot be compared directly, they are different products, even if both are given in cents per kWh. Second: these costs say nothing about the rhythm. Solar and wind electricity are cheap, but not always available; storage and grids cost extra and are not in the table. Third: existing, long-since paid-off installations (such as old hydropower plants) often produce for a few cents, while building the same technology anew turns out more expensive.
For context: new coal or gas plants come in, depending on the fuel price, at roughly 10 to 20 ct/kWh, new nuclear plants rather above that. The comparison shows why wind and sun lead the build-out: they have simply become the cheapest. Whoever argues about energy in future should know such figures, for they reveal whether an argument rests on facts or merely on habit and interests.