Бесплатный фрагмент - Global development of geothermal energy

Global development of geothermal energy

1. Current situation and trends

World leaders. Today, the total installed capacity of geothermal power plants in the world is about 15–16 GW. Geothermal energy is concentrated in a limited number of countries with suitable resources. World leaders include USA, Indonesia And Philippines, which together account for almost half of global power. The top 10 countries by installed capacity of geothermal power plants also include Turkey, New Zealand, Kenya, Mexico, Italy, Iceland And Japan. Collectively, these ten states provide about 93% of the world’s geothermal capacity.

Distribution by region. The global geography of geothermal energy is uneven. On Asia-Pacific (Indonesia, Philippines, Japan, New Zealand, etc.) account for the largest share — about 35–40% of global capacity (about 6 GW). Makes a significant contribution North America (mainly USA and Mexico) — about 30% (almost 5 GW) of installed capacity. IN of Europe geothermal generation is represented in Italy, Iceland and Turkey, with a total of ~3.4 GW (≈20% of the global figure). Africa (mainly Kenya) provides about 6% of global power (~1 GW), and Latin American and Caribbean countries (including Central America, Chile, etc.) accounts for about 4–5% (~0.8 GW). Thus, the leading regions are volcanically active zones “Pacific Ring of Fire”(Southeast Asia, Oceania, West Coast of the Americas) and East African Rift.

Growth rate. In the last ten years, geothermal energy has been developing at a moderate pace, significantly inferior in dynamics to solar and wind generation. The cumulative growth of installed geoelectric power capacity for the period 2013–2023 amounted to about 40–50%. On average it’s about 3–4% per year, which reflects stable but not explosive growth in the industry. Thus, in the 2010s, global capacity increases fluctuated between 0.3–0.5 GW annually. For example, only ~200 MW of new geopower plants were added in 2022, bringing the global total to ~14.6 GW. In 2023, the increase is estimated at only ~0.2 GW. However, local surges are observed: in Turkey in 2010–2020 thanks to government support, the industry grew from ~100 MW to almost 2 GW, in Indonesia over the past decade, capacity has doubled to more than 2.4 GW, and Kenya Since the 2010s, geothermal generation has almost tripled (to ~0.9–1 GW). Thus, the general trend is relatively slow global growth, concentrated in a few countries that are actively increasing investment in geothermal projects.

2. Technological aspects

Basic technologies of geoelectric power systems. Modern geothermal power plants use several types of technologies depending on the characteristics of the resource. For high-temperature fields (dry steam) they are used direct dry steam turbines — for example, the historical stations in Larderello (Italy) and Geysers (USA) operate directly on natural steam. More common settings flash type (with steam extraction), where water from the subsoil, heated to 150–300°C, suddenly boils when the pressure decreases — the released steam is sent to the turbine, and the remaining brine often goes through a second stage of steam extraction (double flash) for maximum generation. For medium and low temperature sources (100–180°C) they are increasingly used binary geopower systems on the organic Rankine cycle (ORC) — the heat of geothermal water is transferred through a heat exchanger to a working fluid (for example, isopentane), which boils and rotates the turbine. Binary stations make it possible to generate electricity even from “colder” resources, where water does not form its own steam, which significantly expands the geographic applicability of the technology. For the 2020s, it is binary plants that dominate among new projects, especially in regions with not very high reservoir temperatures (for example, most new plants in Turkey are binary).

Innovation and advanced technologies. The geothermal energy industry is evolving towards increased efficiency and the development of previously inaccessible resources. One of the key areas is technology enhanced geothermal system (EGS, Enhanced Geothermal Systems), where drilling and fracturing create artificially fractured reservoirs in hot, dry rock. EGS projects make it possible to obtain heat almost anywhere with sufficient drilling depth. Although commercial applications of EGS are still limited, successful pilot projects are showing encouraging results. So, in 2023, a startup Fervo Energy (USA) reported sustainable generation of ~3.5 MW at an EGS pilot site in Nevada — in fact, the first confirmed long-term generation of electricity from “dry” geothermal reservoir. In Europe, EGS technologies are also being tested (projects in France, Great Britain, Germany), although there have been failures — for example, in Pohang (South Korea), an experimental EGS well provoked a noticeable earthquake of magnitude 5.4 in 2017, which led to the freezing of the project. In addition to EGS, we are developing closed geothermal systems (Closed-loop), where the coolant circulates through a closed loop of wells without contact with rocks — such systems potentially eliminate the risk of emissions and can simplify energy production in difficult conditions. Another promising area is supercritical geothermy: drilling to extreme depths (5–7 km) in volcanic zones to achieve supercritical water parameters (> 374°C,> 220 atm). Theoretically, one such supercritical geothermal well can produce 5 to 10 times more power than a conventional well, due to the much greater enthalpy of the fluid. Ultra-deep drilling has already been carried out in Iceland and Italy (the IDDP project in Iceland reached ~500°C), however, supercritical wells face technological difficulties (corrosion, superheated steam destroys equipment) and are still at the research stage. Work is also underway to improve the efficiency of traditional plants — for example, the use of dual-circuit co-generation schemes (simultaneous generation of electricity and heat supply), optimization of reinjection (full reinjection of waste fluid to maintain pressure and heat resources), the use of modern materials and coatings for corrosion resistance, digital monitoring of reservoirs, etc. Interest in geothermy is emerging in related industries: oil and gas companies are investing in geothermal startups, seeing opportunities to use their experience drilling for new energy. Thus, technological progress is gradually reducing costs and expanding the potential reach of geothermal energy.

3. Cost-effectiveness

Cost of electricity. Geothermal generation has an important economic advantage — the ability to provide basic (round-the-clock) power delivery regardless of the weather. However, the capital costs of geopower plants are high (drilling deep wells, creating infrastructure), which is reflected in the cost of electricity production. According to the IEA and IRENA, the average global levelized cost (LCOE) of geothermal electricity over the past decade has been around $0.05–0.09 per kWh. In 2022, thanks to cheaper technologies, there was a decrease in the cost of new projects — according to IRENA, the weighted average LCOE of geoelectric power plants decreased by 22%, to $0.056/kWh. This is still slightly higher than the cheapest forms of renewable energy: in comparison, large-scale solar power plants LCOE was ~$0.049/kWh, and land wind turbines — ~$0.033/kWh in 2022. However, geothermal energy is competitive with traditional fossil fuel generation. For example, the cost of electricity for new coal or gas thermal power plants is usually in the range of $0.05–0.10/kWh (depending on fuel prices and carbon payments), and gas price spikes in 2021–2022. led to an increase in the marginal costs of gas generation to $0.15–0.20/kWh and higher. Thus, with stable operating costs, geothermal plants can provide very competitive electricity prices in the long term, especially in regions with high potential.

Subsidization and support. The development of the geothermal industry requires significant initial investment and overcoming geological risks, so in many countries it is stimulated by government programs. Turkey — a striking example of the successful application of tariff support: from 2010 to 2020. acted “green” tariff $0.105/kWh for geoenergy (guaranteed for 10 years), which attracted private investment and made it possible to increase the capacity of geoelectric power plants by more than 15 times (from 100 MW to ~1.7 GW). IN Indonesia the state also sets increased tariffs for electricity from geoelectric power plants and takes on part of the risks of exploration drilling — there is a special fund and guarantee mechanism that subsidizes the geological exploration stage. USA As part of the new climate policy (Inflation Reduction Act, 2022), federal tax credits for geothermal projects have been expanded: geothermal investors can now receive Investment Tax Credit up to 30% of capital costs or Production Tax Credit ~$0.0275 per kWh of supplied energy. These incentives are comparable to incentives for wind and solar and are intended to revitalize the geothermal sector in the US, especially given EGS development plans. Kenya enjoys the support of international institutions — a mechanism was created with the participation of the World Bank and the African Union Geothermal Risk Mitigation Facility, reducing drilling risks through grants and insurance, which attracted investors to the Olkaria and Menengai projects. IN European Union geothermal projects can receive funding through innovative climate programs, and some countries (for example, Germany, France) provide subsidies or higher market tariffs for small-scale geothermal power plants and especially for pilot EGS plants. Japan after 2011, introduced a tariff of ~¥27–¥40/kWh (≈$0.20–0.30) for small geothermal plants to encourage investors to overcome local resistance and build new facilities. In developing countries of Latin America (Nicaragua, El Salvador, Dominica, etc.), the industry is actively attracting funds from multilateral development banks and donors, which co-finance geothermal plants and infrastructure for the direct use of heat. In general, without support mechanisms (subsidies, tax breaks, guarantees), geothermal energy is developing sluggishly, so the governments of leading leading countries are creating favorable conditions for investors in the industry.

4. Environmental aspect