Renewable energy sources

Who’s winning in the 1.5°C global race?

Courtesy of The Times

There are 6 renewable energy sources available on planet Earth - sun, wind, hydro, geothermal, bioenergy and the ocean.

To achieve net zero and limit the global temperature rise to 1.5°C, increased dependence on renewables at the expense of fossil fuels is essential alongside a few other actions.

Helping the renewables revolution

Energy efficiency and conservation must improve. A couple of very different examples include the continued electrification of the car and less cement production, replaced or mixed with alternatives like graphene. Only this week, I saw a courier on an electrified push bike with sizeable parcel container attached. It reminded me of milk deliveries using electric floats when I was a child - there’s progress for you.

Whole end user sectors must electrify such as transportation which currently relies heavily on fossil fuels. Heating homes and offices needs to switch from gas fired boilers to electric heat pumps.

More reliance on the production and use of green hydrogen as well as other synthetic fuels such as green ammonia and methanol is essential.

Industry also has to embrace carbon capture and storage from all emitting processes (think chimneys with invisible gases) including the use of bioenergies. They may have been sustainably sourced, but the CO2 emissions when burnt for fuel need to be captured as well.

Which country is leading the charge?

Courtesy of Global Energy Statistical Yearbook (Enerdata) and be-the-story

There are a few surprise names in the top ten leading countries for share of renewables in electricity production, including four Latin American countries. I’m more used to reading about Brazil because of the hands off approach, the country’s President, Jair Bolsonaro, took with Covid, when the Pandemic was raging or his alarmingly relaxed attitude to logging companies in the Amazon rainforest. Brazil (84%) currently produces over twice as much renewable electricity as the UK, so who’s the real environmental culprit?

One of the reasons for the surprising results, is the cost reduction in setting up wind and solar power farms. More accessible technology for developing countries, has resulted in a cheap renewable energy supply without being beholden to world markets and other countries for oil, gas or coal, to fire their power stations.

Given the slow but persistent direction of travel, no one can ignore the facts. A gigawatt-hour of electricity from a wind turbine releases 4 tonnes of CO2. The same hour from a coal-fired power plant produces 820 tonnes.

Geothermal

Like oil producing countries, if you’re lucky enough to be an Iceland or a New Zealand, it can cover a significant share of the country’s power demands. (Not sure why Iceland doesn’t appear in the chart above? 100% of their electricity comes from renewable sources).

Heat is captured from the earth’s sub-surface by water or steam, which can then be harnessed when it reaches the surface. Electricity generation requires high or medium temperatures, which is why this type of energy is associated with geologically active parts of the world. Other countries which already tap in, are The Philippines, Kenya and El Salvador.

The big advantage is production is not dependent on the weather, has high capacity capability, which means geothermal power plants can deliver base-load electricity. A bit like nuclear, it’s always on and doesn’t fluctuate like wind energy, for instance.

Hydropower

Hydro has been around the longest. The Greeks were taking energy from flowing water to turn heavy stone wheels to grind grain 2,000 years ago.

It’s extremely cost effective and preferred wherever it’s possible. The shining example is Norway, (top of the league), where nearly all electricity is created this way. The largest plant in the world is the Three Gorges Dam in China. Its 80-100 terawatt-hours per year is enough to supply 70-80 million households.

Solar

With the help of photovoltaics, or solar cells, the UK has been generating electricity, even when the sun doesn’t shine. It is becoming increasingly popular around the world for power generation, heating and desalinating water. Solar cells scale easily, which means access to electricity for people living in remote areas or developing countries, away from power grids is much easier to set-up. Even more so in the last decade, because solar panels have become the cheapest form of electricity.

The alternative technology, is concentrated solar power using mirrors, typically in hotter desert conditions, focusing the sun’s rays to heat molten salts, which in turn creates steam to drive a turbine. The big advantage is the heat remains stored in the salts for weeks and electricity can still be generated long after sunset.

Wind

Similar to solar, because costs are falling, usage is on the rise worldwide. Onshore and offshore capacity has risen 7500% in the past two decades. Strong wind speeds are recorded in many parts of the world but some of the best sites are often in the remotest locations, creating the different challenge of distributing the electricity to where it is needed.

Modern wind power was first developed in Denmark, when horizontal-axis wind turbines were built in 1891 and a 22.8-metre wind turbine began operation in 1897. Today’s new wind power projects have turbine capacities of about 2 MW onshore and 3–5 MW offshore.

Bioenergy

Traditionally, energy is created from the combustion of biomass from wood, animal waste, even traditional charcoal. More modern bioenergy technology includes liquid biofuels produced from sugarcane pulp (Bagasse - after the juice from the cane is harvested), biogas from anaerobic digestion of residues and wood pellet heating systems.

Brazil is the leader in liquid biofuels and has the largest fleet of flexible-fuel vehicles which can run on bioethanol. It’s an alcohol made from the fermentation of carbohydrates in starch crops like corn and sugarcane.

There are also some distinct disadvantages of biomass energy. You need space to grow crops which is already leading to deforestation. It needs high volumes of water and is a high cost alternative compared with some of the other renewables.

Ocean

The most experimental of all the renewable energies at the moment, but not without significant potential if the right amount of investment is made. An obvious home for an island nation blessed with a significant tidal range.

The aim is to capture wave energy using some form of converter. These include oscillating water columns that trap pockets of air to drive a turbine. There are also converters that use wave motion and others which make use of height difference between waves.

Seagreen

The first offshore turbine, 27km from the Angus coast in the North Sea, started generating electricity this week (Aug 2022). The JV between TotalEnergies (51%) and SSE Renewables (49%), has permission for 150 turbines of which 114 are now installed. The site will be capable of powering two-thirds of all Scottish homes (1.6 million) next year. The power is to be exported to the grid via a new substation near Dundee, which will alas, leak south for distribution around the UK.