Type: Process Essays
Sample donated: Elvira Drake
Last updated: July 28, 2019
EmpiricalreviewSeveral studies on rooftop solar have so far beenconducted and concluded. These findings are based on actual observations andmeasured phenomena unlike theoretical review that is based on theories andbeliefs. Previous research on rooftop solar in urban centres have focused moreon quantifying the potential of various cities as initiatives to establishwhether the projects is economic viable and can be used to offset reliance onfossil based fuels in electricity generation.
Indian government has taken astep forward by setting a target of 40GW of rooftop solar PV deployment acrossher cities and upcoming urban centres by 2022. The target is termed overambitious by many though the Indian government is putting up measures toaddress the challenges outlined and faced so far by the ongoing deploymentacross the country. Estimationof rooftop solar PV potential in urban centresIn 2009, the Energy and Resource Institute, TERI, NewDelhi came up with a master plan in an attempt to make Chandigarh a solar citythat was among the earliest efforts by the Indian government to deploy rooftopsolar PV (TERI, 2009). MNRE in 2014 launched sixty solar cities across India whoseobjective was to meet at least 10% of the expected energy requirements targetingroof mounted solar in urban centres. This was aimed at addressing increasingdemand of energy across the country characterized by high population rateleading to rapid urbanization (MNRE, 2015). Bridge to India released a report in 2013 ofestimating the rooftop solar potential of Delhi using Google Map Earth forestimating and Wikimapia for classifying the building into three maincategories namely residential, commercial and industrial across the city ofDelhi. It was concluded that 2GW of electricity can be generated using rooftopsolar.
This can be a great achievement with a city total peak demand of 6GW (Bridge to India, 2014). Later in 2015, a city of Patnawas estimated to have a rooftop solar potential of 759MW whereas anticipatedpeak demand was found to be 600MW from the study carried by Bridge to India. Thepotential exceeded the peak demand suggesting excess electricity generated canbe exported to nearby cities through national grid (Bridge to India, 2015) Potential estimates of roof mounted solar in urbancentres have so far provided promising results and opportunities of utilizingroof for power generation globally. The great city of Mumbai in India has anaverage total demand of 3GW according to a study carried. Rooftop solarpotential of approximate 1.72GW was estimated by applying satellite basedassessments using google maps and google earth incorporated with site visits toascertain electricity use across all the sectors of the city. 3D models wereused to extrapolate the suitable area for rooftop solar use. It was concludedthat more than 1.
72GW of electricity can be generated by using rooftop solaracross the city (MNRE, 2016). A need for further study on the points of sinksto determine the nature of off-peak and peak demands can be useful if roofmounted solar is to be effectively utilised. This requires corporation andsupport among all the stakeholders including utility companies. J.
M Pearce et al, 2010 argued that resources todeploy solar PV in urban centres are not the main limiting factors. A five-stepprocedure was used to quantify rooftop solar potential to be used for theregion of Ontario using GIS and advanced feature extraction algorithms toestimate Ontario rooftop solar PV potential. FIT policy was found to have thepotential to facilitate an initiation to significant rooftop solar deploymentin urban centres. A more in-depth analysis of roof area population data points fromthe municipal was recommended that can be used for the purpose of estimates asthe municipal lack data of the buildings and land use (J.M. Pearce et al, 2010).A research gap exists there for identifying more challenges faced by rooftopsolar deployment in such areas that can aid all stakeholders in planning for such. John Byrne et al, 2014 conducted a study to estimaterooftop solar electric potential of the city of Seoul, South Korea by applyingarc-GIS for estimation using cartographic information of 2002 and AutoCAD 2013for extraction of suitable roof area for solar use.
It was concluded that atotal of 11.255GW can be generated by using rooftop solar in the cityrepresenting 30% city total electricity use. They argued that assessment of cities’rooftop solar PV potential is vital since it is the only resource that each countrypossesses (Byrne et al, 2015). Rooftop solarPV potential of Gangnam district of Seoul was estimated by using a three-stepprocess involving data collection and conversion, building shadow analysis byapplication of Hillshade analysis and estimation of available rooftop area. It wasconcluded that 4903079m2 on average can be used for electricitygeneration through solar representing 65.22% of the total roof area in thatdistrict.
The method was argued to be simple to use and accurate and leastexpensive compared to others despite some challenges encountered in the process(Taehoon Hong et al, 2016). A detailed assessment of technical rooftop solar PV potentialwas conducted using DHS Lidar data set that covered 23% of building stock and40% of USA nationwide population. For regions without Lidar data, leveraged DHSLidar data was used to build models for estimating the total amount of suitableroof area for solar utilization. The estimated technical potential was found tobe 1118GW of installed capacity and 1432TWh of total annual electricity sales (Ryanet al, 2016). It was concluded that the estimates were greater than previousstudies by NREL estimates of 800TWh of annual nationwide generation and 664GWof installed capacity (Lopez at al, 2012). M. Luqman et al, 2015 carried astudy by estimating the rooftop solar energy potential of Punjab government servantshousing society using arc-GIS model and concluded that a potential of 399613072KWhwas achievable that accounted for 11% of total energy consumption of the entirecommunity. That represented high potential despite the fact that the study did notutilize all the available roof area in the entire institutions.
A highgeneration is achievable if all the roof areas are considered (M. Luqman et al,2015). The CBD of the city of Johannesburg was estimated tohave a rooftop solar PV potential of approximately 22.6MW of electricitycapacity representing less than 1% of city’s current electricity consumption. Thestudy was carried using GIS and Google earth pro for estimations with the helpof PV watts calculator. The low potential capacity was attributed to the natureof buildings and congestions thus shading taking the larger party of the roofarea. The research concluded rooftop solar PV deployment with the CBD of cityof Johannesburg is not economic feasible (Ntosoane, 2017).
Private sector and donor funded projects in Kenya arethe leading in solar PV deployment. The rapid use of solar PV is promoted bythe government initiative of tax exemptions of all solar PV related productsincluding panels and inverters. Rooftop solar has not been well utilized acrossthe country despite the fact that solar PV use requires large pieces of land thuscompeting with other land use. Learning institutions and commercial buildingsare now turning to use of rooftop solar as they try to offset high electricitybills from fossil based fuels (MoE&P, 2015). No study has been done assessthe rooftop solar potential of Nairobi city despite having the best average solarirradiance of 4.5KWh/m2 throughout the year. Nairobi remains to bethe hub of all economic activities of Kenya and her neighbour nations. There isneed to look for ways to deploy use of solar using roof area to offset overreliance on thermal generation and hydro power that is severely affected bydrought experienced within the country (citation).
Challengesand barriers to renewables including rooftop solarMany studies andanalyses have been conducted to assess the challenges and barriers to scalingup renewable energies worldwide. A survey was conducted to assess the barriersto rooftop solar PV in Puducherry smart grid pilot project in India. It wasconcluded that consumer awareness of rooftop solar PV was the major challengecompared to initial costs and consumer payback period. A suggestion to deployrooftop solar in public places such as schools, hospitals and hotels as meansof creating awareness to the members of the public was recommended. Consumers thosehad prior knowledge preferred to use net and gross metering to deploy roofmounted solar (Ramakrishna Kappagantu et al, 2015).