Solar Power: A viable solution for CO2 mitigation?

If you have been following my posts recently, you may have noticed that I have been talking a lot about solar technologies. Obviously, it all sounds absolutely brilliant in theory and the research effort that goes into developing innovative ways to harness solar energy is changing the face of humanity forever.

There are many challenges that come to surface in practice however and should be considered carefully. 

In this post, I want to suggest that solar power is a serious contender for our future energy needs, but there are several factors that determine how viable solar energy is as an option for energising the future. 

Woooo!! There have been cost reductions for solar PV.

Economic factors is one of the reasons why fossil fuels have dominated the energy mix relative to lower-carbon alternatives (World Economic Forum, 2013). Over the past decade or so, the remarkable cost reductions for solar PV have made it competitive with conventional, fossil fuel based grid power (Nelson et al, 2014). 

Reduction and projected reductions in the cost of PV (Source: Nelson et al, 2014)

Mature Status 

The mature status of the key solar technologies e.g. PV and solar thermal, make them key players in the energy world. The recent growth in the use of PV technology (~40%/yr) and rapid reduction in costs (~20% per doubling of capacity) is impressive given the timeframe (IEA, 2010) cited by Nelson et al (2014). This has surpassed initial expectations.  

Solar power on a large-scale?

According to the IEA's Technology Roadmap for Solar Photovoltaic Energy (2014), it is projected that solar power could generate 22% of world’s electricity by 2050. Solar energy is a viable contender for CO2 mitigation. In fact, the total installed capacities for solar PV have increased tremendously across the world.

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Emissions mitigation using solar energy? 

Do you know what a 'carbon emission intensity' is? 

A carbon emission intensity is essentially a measure of the amount of CO2 or CO2 equivalent (CO2 eq) (i.e. non-CO2 greenhouse gases) emitted per unit of energy generated (He and Liu, 2004). This indicator is useful for assessing the impact of an energy technology. The concept of alternative energy strives to find a replacement for fossil fuels, but these technologies still involve some energy during the manufacture process. This needs to be included in assessments of the amount of carbon dioxide emissions mitigated by a renewable energy technology. 

As with many of the assessments of the extent to which technologies can reduce emissions, it is not possible to give a definite answer. Major flaw I know! This is especially the case in a world where we are uncomfortable with the notion of uncertainty, since it makes decisions harder to implement. Even so, I think it is important for people to understand the factors that influence the efficacy of a particular technology to mitigate emissions.

As if the climate change issue was not complicated enough, we now have the challenge of convincing countries to bring energising the future onto the top of their agendas.  

"Solar energy can help mitigate carbon emissions by replacing more carbon intensive sources." - Nelson et al (2014)

The amount of emissions mitigated depends on (adapted from Nelson et al, 2014):

-       The amount of conventional heat/power displaced

-       The carbon intensity of displaced energy sources

-       The amount and type of energy consumed in manufacture, installation and operation.
-       The location or context of implementation

As such, we should be careful of various interpretations of emissions mitigation. How do we set the baselines for comparative purposes? Are we assessing on a country by country basis? How do we even rate the degree to which emissions are reduced given the different contexts to which technologies are applied? 

In terms of solar energy, solar PV and solar thermal are the most mature technologies and have already implemented at the commercial scale. The previously low level of solar energy utilization has now paved way for price reductions and cheap solar PV (Devabhaktuni et al, 2012). For example, solar PV production in China has sky-rocketed and the costs are now one of the cheapest in the world (Zhang and He, 2013). This has partly been due to the rigorous policies e.g. 12th Five-Year Plan.

http://blog.comparemysolar.co.uk/minimum-price-of-56-eurocent-for-chinese-solar-panels/

Solar PVs are now economically competitive. The capacity of PV power installed globally exceeded 100 MWp in 1992 in 2002 and 100 GWp early in 2013. This is an average growth of ~40% per annum (Nelson et al, 2014).

Aside from the PV market, solar hot water is also a popular technology. In fact, it accounted for 235 gigawatts of thermal power (GWth) by the end of 2011 (IEA, 2013) cited by Nelson et al (2014). The Chinese case is impressive, with solar hot water being cost-effective (114W of total cumulative installed capacity (GWth)), and often applied for high-rise apartments (Shi et al, 2013) . The advantage of this technology is the ease of application in domestic contexts.

In terms of solar concentrator systems, Spain and the USA are the current leaders. These systems are advantageous since light collecting surfaces can be rotated with time of day/season in order to capture the sun’s radiation (Nelson et al, 2014).

What have countries done so far?

Solar PVs have contributed significantly to electric power supply and this is evident in the German case where in 2013, PV-generated power totalled 30 TWh and covered approximately 5.7
percent of Germany’s net electricity consumption (Wirth, 2014). For more on the role of feed-in-tariffs etc., the economics and frameworks for integrating renewables, and photovolataics in Germany CLICK HERE.

Other countries are now looking to follow suit, for instance China and Japan have looked to increase their rooftop installations. China is currently pushing for solar power as a key technology for mitigating emissions. Both China and Japan going head-to-head in the race for the largest solar market. 

Many countries have adopted the use of solar panels, but there is an extra effort to increase large-scale solar plants. Reuters reported that the TuNur project aimed to generate clean energy from a giant solar plant in the Tunisian Sahara, which will be connected to Europe's electricity grid via. an undersea cable. This project demonstrates how important solar is for energising the future.

http://www.independent.co.uk/environment/green-living/saharan-sun-could-power-uk-homes-in-8bn-plan-to-build-100-sq-km-solar-farm-9807292.html

Saharan solar power opens energy corridor to Europe

VIDEO>>> http://www.sciencedaily.com/videos/c754f9f590e84404c58848c9091a6bc1.htm <<<

Counterintuitively, the adoption of solar power is still below its potential. Why is this so?

The issue lends itself to the problem of power generation and distribution. One major problem of alternative technologies e.g. solar, wind etc. are the highly variable energy sources (Cochran, 2012). This has largely been alleviated by proposals for better storage solutions (BBC, 2014). However, storage technologies often increase the costs of implementation (Dunn et al, 2011). Many people have recognised that concentrator systems can be used to manage the mismatch between supply and demand, since thermal energy can be stored (Nelson et al, 2014).

In evaluating technologies, I refer to the triage of economic, technical and policy factors. 

What do I mean by technical/economic factors? 

Here are some things to take into account (adapted from Nelson et al, 2014): 

- Available resource; 
- Power conversion efficiency; 
- Cost per unit capacity; 
- Operation costs; 
- Life cycle and carbon intensity

The amount of solar capacity deployed depends on (adapted from Nelson et al, 2014):

-       (i) the cost of the PV electricity relative to alternatives

-       (ii) availability of the PV technology

-       (iii) the fraction of renewable power that can readily be accommodated in the electric grid

-       (iv) regulatory issues, such as building and planning regulations, and policy measures

Potential Application in Emerging Economies - It has enormous relevance for remote areas!

With low levels of infrastructure and a lack of experience in some areas in developing countries, solar power technologies have great prospects for helping these countries align their development trajectories to low-carbon sources (Kaygusuz, 2012). In many ways, the ease of adoption of new technologies for powering the future is much greater in emerging economies. What you find is that in developed countries, energy infrastructure is mature and hence, this makes the integration of new technologies harder to achieve (but not impossible of course). Also, solar power is directly relevant to developing countries due to the abundance of solar resource and storage could soon be a cost effective option (Forsyth, 2014).

In terms of provision of energy resources for rural areas, solar energy is the way forward. This relies more on the battery storage technologies for lighting and communications etc. All in all, the off-grid applications of solar energy are as useful as grid applications (Raman et al, 2012), especially for rural electrification.

http://www.ecology.com/2013/07/18/printed-power-to-light-the-world%E2%80%99s-darkness/

The problem here? Surely it must be cost!

Storage of electricity using batteries is
 fairly efficient (>80%), but expensive (adding $0.2/kWh) with a lifetime of ten years or less (Nelson et al, 2014). In the case of off-grid generation, the relatively high cost of battery storage can double the overall cost of the electricity and the carbon intensity (Chan et al, 2014) cited by Nelson et al (2014). This is demonstrated in the case of India.

How about land area and other costs?

Raman et al (2012) mentioned that the capital cost and the land requirement for a solar energy based system is higher than all other renewable energy power generation systems. However, the operation and maintenance costs are low. 

Solar energy is not the only solution!

Solar energy cannot act alone. The mismatch between supply and demand is a theme that transgresses all areas of energy technology and management. Since solar energy is highly seasonal, depends on climatological factors e.g. clouds and also has high diurnal variations, something must be done to alleviate the impact of variability. Storage is one option, but how about combining with other sources? 

Renewable energy resources can complement each other, so this supports a move towards a more diverse renewables mix to help the electricity system accommodate for variability. 

In the German case, wind and solar generation can complement each other and work side-by-side on a daily and seasonal basis (Fraunhofer Institute For Solar Energy Systems, 2012). 

The future of solar?

Aside from price, other factors are now important in influencing the deployment levels of solar (EPIA, 2011). 
The potential for solar power is very great, but there are obstacles to be overcome in managing the level of penetration i.e. variability in electricity supply, which can increase the risk of blackouts. 

Solar is a serious contender for future energy needs, with many technologies in the maturity phase. The development of solar fuel cells could reduce emissions significantly from the transport sector.

To move forward, I think there should be more effort towards developing storage solutions technologically and economically. Obviously, the dissemination of technology into the commercial sphere can only happen with stimulation from government/supportive regulative policies. 

Here's the biggest problem though. Is it ironic that in trying to reduce emissions, solar energy is having an impact on the environment through land space. Solar energy is constrained by limited land area and low insolation in many countries. Apart from solar concentrator systems, other solar technologies may not be sufficient for energy-intensive industrial processes. Maybe, the increased roll-out of small-scale units distributed over a greater area could solve this.  The night-time is still a problem. 

Summary:

What kinds of things can increase the role of solar energy in carbon mitigation? 

-       Reduce costs!

-       Improve the ease at which technologies can be integrated and achieving greater penetration: developing technologies for power distribution and storage; tackling the problem of mismatch between supply and demand

-       Focus on policy and regulation

Despite this, solar may become the largest global power source by 2050 (Roca, 2014) and has huge potential. 

BUT...surely solar is not the silver-bullet to our future energy needs! Follow me as I explore other technologies....

Devabhaktuni et al (2012) Solar energy: Trends and enabling technologies

He, J., & Liu, B. (2004). Analysis of carbon emission intensity as the main index for greenhouse gas emission mitigation commitments. Qinghua Daxue Xuebao/Journal of Tsinghua University(China), 44(6), 740-743.

Kirkegaard, J. F., Hanemann, T., Weischer, L., & Miller, M. (2010). Toward a Sunny Future?: Global Integration in the Solar PV Industry (No. WP10-6). Peterson Institute for International Economics.

Zhang, S., & He, Y. (2013). Analysis on the development and policy of solar PV power in China. Renewable and Sustainable Energy Reviews, 21, 393-401.

Shi, J., Su, W., Zhu, M., Chen, H., Pan, Y., Wan, S., & Wang, Y. (2013). Solar water heating system integrated design in high-rise apartment in China. Energy and Buildings, 58, 19-26.

Dunn, B., Kamath, H., & Tarascon, J. M. (2011). Electrical energy storage for the grid: a battery of choices. Science, 334(6058), 928-935.

Forsyth, T. (2014). International investment and climate change: energy technologies for developing countries. Routledge.

Kaygusuz, K. (2012). Energy for sustainable development: A case of developing countries. Renewable and Sustainable Energy Reviews, 16(2), 1116-1126.

Chan et al. Potential of solar photovoltaic technologies for rural electrification and carbon emissions mitigation: the case of India, Report, Grantham Institute for Climate Change (2014).

Fraunhofer Institute For Solar Energy Systems ISE,Photovoltaics Report, December 2012

EPIA, Solar Photovoltaics Competing in the Energy Sector – On the road to competitiveness, (September 2011)