Nowadays, this topic plays a crucial role in Argentina since different public policies for environmental and social inclusion issues have recently been implemented, especially planning strategies, projects and laws to promote RE. The national Law 26190 to promote the use of RE sources for electric energy generation was passed in 2006. It establishes as an objective a coverage of 8% of the national electricity demand by 2016 through RE sources. The law introduces feed in tariffs for wind, biomass, small scale hydro, tidal, geothermal and solar power for a period of 15 years [
4]. However, at the end of 2014, RE represent only 1% of the total electricity supply and 1.7% of the installed generation capacity. While wind contributed 265 MW, and biomass 1.150 MW, only 1 MW was provided by PV [
5]. The poor results motivated a new law enacted in September 2015. It is the national Law 27191, which provides financial arrangements and establishes new RE penetration goals. The 8% objective for national electricity demand coming from RE should now be achieved by 2017, but there is also a new mid-term objective of 25% RE penetration by 2025 [
6]. Furthermore, several provinces of the country decided to take their own measures and enacted their own laws for promoting RE.
In this paper, a technical, economical and social assessment of the photovoltaics (PV) energy supply potential for the Province of Salta in the frame of a net-metering law is presented. The province is located in the northwest of the country and has a high potential for energetic exploitation, principally of solar and biomass resources [
7]. The strategy that has been followed by this province includes a RE plan, a law for RE promotion and a net-metering law. The objective of the present study is to analyze the PV potentials and provide recommendations to activate this potential, while considering technical, economical and social constraints, derived from a participatory process.
The paper is structured as follows: First, the rest of the Introduction Section is dedicated to the explanation of the RE promotion framework in the Province of Salta and to the state of the art of PV potential evaluation. Second, the methodology for the participatory consultation, and the PV technical and economical assessment is explained. Third, the results are presented and discussed. Fourth, in the final section, conclusions are drawn and recommendations are given.
1.1. Renewable Energy Promotion Framework in the Province of Salta
In the Province of Salta, a planning process was set up to promote and encourage the use of RE sources. This process began in 2011, lead by the secretary of energy of the province and with the participation of various public and private institutions [
8]. The first result of this process was a RE plan for the province that appeared in 2014. This plan seeks to promote the generation and use of RE to meet the energy requirements of the inhabitants of the province, diversify the energy matrix and improve industrial competitiveness and quality of life [
7]. One of the initial objectives of the plan was to establish a reliable framework to strengthen public and private investment to adopt clean energy sources. Two laws were enacted in this context: law No. 7823—“
Régimen de Fomento para las Energías Renovables” (Promotion scheme for Renewable Energies) and law No. 7824 “
Balance Neto. Generadores residenciales, Industriales y productivos” (Net metering. Residential and industrial electricity generators). Both laws were enacted in 2014 and their corresponding regulations were completed in February 2015.
The law No. 7823 promotes the use, production, research, development and sustainable use of RE. The government gives different benefits to natural or legal persons who develop, manufacture and/or install technologies for harnessing RE. The most important include: (1) exemption from provincial taxes (up to 100% for a 10 year period); (2) tax credits for up to 70% of the value of the investment in equipment, with five years of grace and without interest; and (3) the provincial government assists to obtain credits and helps with technological, economic, financial and administrative aspects.
The net-metering law addresses residential and industrial electricity generators with the intention of motivating the installation of RE generation plants. The notion of “Net Balance”, in the legislation of the Province of Salta, refers to the difference between the amount of electricity consumed from the grid and the amount of generated RE energy that is fed into the grid by a certain user during a certain period of time. The law promotes the installation of RE electric generators in private homes, businesses and industries (installation of up to 30 kWp for residential users and up to 100 kWp for businesses and industries). All electricity generated beyond own needs and fed into the grid is bought by the local electricity company at a differential rate. This rate varies depending on the RE source and is in general higher than the current energy final price for consumers. The highest of the rates is the one paid for energy produced with PV, which is currently around ten times higher than the final price paid for electricity by average users. Users wishing to access the net-metering mode must have the installation with all technical requirements and allow for supervision by the energy distribution company. The obligation of the users includes the payment of an initial connection fee and yearly inspection fee. The law contemplates as additional promotion measure that all energy generated by the user will be bought at the differential rate for the first two years. The users continue paying the usual energy price for every kWh that they are receiving from the grid. It is only from the third year that the net balance is adopted.
1.2. State of the Art of Photovoltaic Potential Evaluation
The evaluation of PV potential usually follows a top-down approach in which the theoretical, the technical and the economic PV potential are estimated consecutively [
9]. The theoretical potential concerns the evaluation of solar radiation availability. The technical potential is a fraction of the theoretical one and incorporates the consideration of energy transformation efficiency of the PV-panels, inverters and further components of the installation. The economic potential is based on “soft” factors which may change over time [
10]. This presents the amount of energy that can be generated by PV-installations under the current or expected local costs structure, legislation and the public acceptance of the technology [
9].
In situ measurements of solar radiation, satellite data, GIS-based procedures, reanalysis data or a combination of these are common data sources to estimate the theoretical and technical PV energy generation potential. The use of a data source depends on the study area.
In situ measurements are considered the most accurate sources and normally serve to validate the other alternatives [
11]. However, their availability is limited and their access is restricted. Even European weather station networks, recording solar radiation data, are not dense enough in order to provide proper coverage [
12,
13] and data sets are not necessarily freely accessible for the broad public. On the other hand, global solar radiation and temperature data derived from satellite images are available for most part of the world in temporal resolutions higher than hours, at no cost in many cases, but their accuracy depends strongly on the algorithms used to deal with cloud coverage and to derive the variables of interest from the sensors. Algorithms such as the Heliosat in its different versions [
14] and the one used by the Land Surface Analysis Satellite Application Facility (LSA-SAF) have been validated in multiple locations [
15,
16,
17,
18,
19] but there are accuracy problems in mountainous regions [
20,
21]. Reanalysis data sets provide global coverage and there are several freely available data sources (see, e.g., [
22]), but these have relatively low spatial and temporal resolutions compared to data derived from satellite images. Moreover, solar radiation models integrated in GIS tools have been widely used to estimate solar radiation and PV technical potential in areas with complicated topography and in urban environments [
23,
24,
25,
26]. These rely, however, on other atmospheric variables that must be retrieved from
in situ measurements, satellite images and/or reanalysis data. Examples of methodologies combining different sources have been proposed for the whole world [
27], Europe [
28], for several detailed studies of cities and municipalities (e.g., [
29,
30,
31]), and for comparing different types of technologies and incentive programs for PV (e.g., [
32,
33,
34]).
The calculation of PV technical potential varies widely in scientific literature. On the one hand, there are studies where the PV yield is calculated by merely multiplying the total solar energy cumulated in a surface in a year by a certain efficiency factor (see, e.g., [
35]). On the other hand, there are cases where the yield is calculated in high temporal resolution, considering effects of shadowing, ambient and roof-top temperature (see, e.g., [
36,
37,
38]).
Economic PV potential is assessed taking into consideration in-time-changing factors that are decisive for the realization of projects and the adoption of PV. Regulatory mechanisms as feed in tariffs and net-metering laws as well as the local cost structure (installation, capital and electricity costs) are quantitative factors that are usually used for the economic PV potential evaluation [
39]. An attractive economic potential based on these factors is necessary, but does not guarantee the market success of PV [
40]. Diffusion and acceptance barriers perceived by potential PV investors must be also identified and overcome. Participatory processes constitute a widely applied strategy to identify these barriers and propose alternatives to overturn them [
41,
42,
43,
44].
Concerning only the quantitative factors of the economic potential, existing literature relies either on cost-related or on investment attractiveness figures [
45]. The levelized cost of electricity (LCOE) is the widest used cost-related indicator, but is also target of strong criticism [
46]. LCOE serves to compare the costs of different energy sources while correcting differences in the operation and investment time horizons. This requires, however, assumptions about discount rates, which are difficult to make in context of high uncertainty [
47]. Typically, investment attractiveness figures for PV are payback periods, net present value (NPV) and internal rate of return (IRR). NPV allows an intuitive assessment of individual projects, but has the same drawback as LCOE, since it depends strongly on the applied discount rates. The other two indicators do not require assumptions about discount rates, but still have their own limitations. Payback periods tend to overestimate future returns, because they do not incorporate the time value of money. IRR does consider the time value of money, but is not an appropriate indicator, when evaluating projects with different time horizons and scales [
45].